The Effect of DNA Methylation on DNA-Protein Interactions and on the Regulation of Gene Expression

1986 ◽  
pp. 235-240 ◽  
Author(s):  
Walter Doerfler
2021 ◽  
Author(s):  
Seth W Cheetham ◽  
Yohaann M.A Jafrani ◽  
Stacey B Andersen ◽  
Natasha Jansz ◽  
Adam D Ewing ◽  
...  

DNA-protein interactions and cytosine methylation control eukaryotic gene expression. Here, we present an approach to simultaneously detect cytosine methylation and DNA-protein interactions from single molecules, through selective sequencing of adenine-labelled DNA. Applying this approach to LaminB1-associated heterochromatin domains, we identify strict CpG methylation maintenance at transcriptional start sites amid a generalised relaxation of methylation, potentially to prevent ectopic aberrant heterochromatic gene expression.


The Nucleus ◽  
2021 ◽  
Author(s):  
Gaurab Aditya Dhar ◽  
Shagnik Saha ◽  
Parama Mitra ◽  
Ronita Nag Chaudhuri

2010 ◽  
Vol 88 (6) ◽  
pp. 885-898 ◽  
Author(s):  
Michèle Amouyal

The way a gene is insulated from its genomic environment in vertebrates is not basically different from what is observed in yeast and Drosophila (preceding article in this issue). If the formation of a looped chromatin domain, whether generated by attachment to the nuclear matrix or not, has become a classic way to confine an enhancer to a specific genomic domain and to coordinate, sequentially or simultaneously, gene expression in a given program, its role has been extended to new networks of genes or regulators within the same gene. A wider definition of the bases of the chromatin loops (nonchromosomal nuclear structures or genomic interacting elements) is also available. However, whereas insulation in Drosophila is due to a variety of proteins, in vertebrates insulators are still practically limited to CTCF (the CCCTC-binding factor), which appears in all cases to be the linchpin of an architecture that structures the assembly of DNA–protein interactions for gene regulation. As in yeast and Drosophila, the economy of means is the rule and the same unexpected diversion of known transcription elements (active or poised RNA polymerases, TFIIIC elements out of tRNA genes, permanent histone replacement) is observed, with variants peculiar to CTCF. Thus, besides structuring DNA looping, CTCF is a barrier to DNA methylation or interferes with all sorts of transcription processes, such as that generating heterochromatin.


1994 ◽  
Vol 14 (10) ◽  
pp. 6635-6646
Author(s):  
J A Diehl ◽  
M Hannink

Protein-protein interactions between the CCAAT box enhancer-binding proteins (C/EBP) and the Rel family of transcription factors have been implicated in the regulation of cytokine gene expression. We have used sequence-specific DNA affinity chromatography to purify a complex from avian T cells that binds to a consensus C/EBP motif. Our results provide evidence that Rel-related proteins are components of the C/EBP-DNA complex as a result of protein-protein interactions with the C/EBP proteins. A polyclonal antiserum raised against the Rel homology domain of v-Rel and antisera raised against two human RelA-derived peptides specifically induced a supershift of the C/EBP-DNA complex in mobility shift assays using the affinity-purified C/EBP. In addition, several kappa B-binding proteins copurified with the avian C/EBP complex through two rounds of sequence-specific DNA affinity chromatography. The kappa B-binding proteins are distinct from the C/EBP proteins that directly contact DNA containing the C/EBP binding site. The identification of a protein complex that binds specifically to a consensus C/EBP site and contains both C/EBP and Rel family members suggests a novel mechanism for regulation of gene expression by Rel family proteins.


2018 ◽  
Vol 4 (11) ◽  
pp. eaau6986 ◽  
Author(s):  
Lu Wang ◽  
Patrick A. Ozark ◽  
Edwin R. Smith ◽  
Zibo Zhao ◽  
Stacy A. Marshall ◽  
...  

The tet methylcytosine dioxygenase 2 (TET2) enzyme catalyzes the conversion of the modified DNA base 5-methylcytosine to 5-hydroxymethylcytosine. TET2 is frequently mutated or dysregulated in multiple human cancers, and loss of TET2 is associated with changes in DNA methylation patterns. Here, using newly developed TET2-specific antibodies and the estrogen response as a model system for studying the regulation of gene expression, we demonstrate that endogenous TET2 occupies active enhancers and facilitates the proper recruitment of estrogen receptor α (ERα). Knockout of TET2 by CRISPR-CAS9 leads to a global increase of DNA methylation at enhancers, resulting in attenuation of the estrogen response. We further identified a positive feedback loop between TET2 and ERα, which further requires MLL3 COMPASS at these enhancers. Together, this study reveals an epigenetic axis coordinating a transcriptional program through enhancer activation via DNA demethylation.


2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 1041-1041
Author(s):  
Joaquina Martínez-Galan ◽  
Sandra Rios ◽  
Juan Ramon Delgado ◽  
Blanca Torres-Torres ◽  
Jesus Lopez-Peñalver ◽  
...  

1041 Background: Identification of gene expression-based breast cancer subtypes is considered a critical means of prognostication. Genetic mutations along with epigenetic alterations contribute to gene-expression changes occurring in breast cancer. However, the reproducibility of differential DNA methylation discoveries for cancer and the relationship between DNA methylation and aberrant gene expression have not been systematically analysed. The present study was undertaken to dissect the breast cancer methylome and to deliver specific epigenotypes associated with particular breast cancer subtypes. Methods: By using Real Time QMSPCR SYBR green we analyzed DNA methylation in regulatory regions of 107 pts with breast cancer and analyzed association with prognostics factor in triple negative breast cancer and methylation promoter ESR1, APC, E-Cadherin, Rar B and 14-3-3 sigma. Results: We identified novel subtype-specific epigenotypes that clearly demonstrate the differences in the methylation profiles of basal-like and human epidermal growth factor 2 (HER2)-overexpressing tumors. Of the cases, 37pts (40%) were Luminal A (LA), 32pts (33%) Luminal B (LB), 14pts (15%) Triple-negative (TN), and 9pts (10%) HER2+. DNA hypermethylation was highly inversely correlated with the down-regulation of gene expression. Methylation of this panel of promoter was found more frequently in triple negative and HER2 phenotype. ESR1 was preferably associated with TN(80%) and HER2+(60%) subtype. With a median follow up of 6 years, we found worse overall survival (OS) with more frequent ESR1 methylation gene(p>0.05), Luminal A;ESR1 Methylation OS at 5 years 81% vs 93% when was ESR1 Unmethylation. Luminal B;ESR1 Methylation 86% SG at 5 years vs 92% in Unmethylation ESR1. Triple negative;ESR1 Methylation SG at 5 years 75% vs 80% in unmethylation ESR1. HER2;ESR1 Methylation SG at 5 years was 66.7% vs 75% in unmethylation ESR1. Conclusions: Our results provide evidence that well-defined DNA methylation profiles enable breast cancer subtype prediction and support the utilization of this biomarker for prognostication and therapeutic stratification of patients with breast cancer.


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